For various reasons, including end-stage renal disease or E.S.R.D., illness, injury or surgery, patients may require replacement or supplementation of their natural renal function in order to remove excess fluid and/or metabolic waste products from their blood. Hemodialysis employing hollow fiber membranes, and peritoneal dialysis are among the most common dialysis techniques. More recently, the use of devices employing the passage of blood between two relatively moving surfaces, and more particularly, between two relatively rotating surfaces which can create Couette flow and so-called Taylor vortices has been proposed for dialysis. Examples of such devices and systems are described in U.S. Pat. Nos. 6,863,821 and 7,182,867 to Moriarty et al., and U.S. Publications Nos. 2006-0278581 (Ser. No. 11/465,952) and 2007-0181500 (Ser. No. 11/734,579), also to Moriarty et al., which are incorporated herein by reference.
Further examples of such devices and systems for dialysis may be found in U.S. Patent Application Publications 2004-0238445, 2006-0041216 and 2007-0193941 to McLaughlin et al., also incorporated by reference herein. Application No. 2006-0041216 specifically describes employing such a device in a two-stage dialysis procedure in which at least one of the stages employs a Taylor-vortex enhanced blood filtration device. However, the system described in that application is largely directed at avoiding the need for large volumes of new replacement fluid by generating replacement fluid from the fluid removed from the patient. It also discloses recycling dialysate employed in the dialysis. The disclosed process and system, however, are potentially substantially slower than other dialysis systems, adding to the burden of lengthy procedure times already experienced by most hemodialysis patients.